/*
 * Copyright 2018 Alfresco, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.activiti.runtime.api.impl;

import java.util.ArrayList;
import java.util.List;

import org.activiti.api.model.shared.model.VariableInstance;
import org.activiti.api.runtime.shared.query.Page;
import org.activiti.api.runtime.shared.query.Pageable;
import org.activiti.api.runtime.shared.security.SecurityManager;
import org.activiti.api.task.model.Task;
import org.activiti.api.task.model.builders.TaskPayloadBuilder;
import org.activiti.api.task.model.impl.TaskImpl;
import org.activiti.api.task.model.payloads.AssignTaskPayload;
import org.activiti.api.task.model.payloads.CandidateGroupsPayload;
import org.activiti.api.task.model.payloads.CandidateUsersPayload;
import org.activiti.api.task.model.payloads.ClaimTaskPayload;
import org.activiti.api.task.model.payloads.CompleteTaskPayload;
import org.activiti.api.task.model.payloads.CreateTaskVariablePayload;
import org.activiti.api.task.model.payloads.DeleteTaskPayload;
import org.activiti.api.task.model.payloads.GetTaskVariablesPayload;
import org.activiti.api.task.model.payloads.GetTasksPayload;
import org.activiti.api.task.model.payloads.ReleaseTaskPayload;
import org.activiti.api.task.model.payloads.UpdateTaskPayload;
import org.activiti.api.task.model.payloads.UpdateTaskVariablePayload;
import org.activiti.api.task.runtime.TaskAdminRuntime;
import org.activiti.engine.TaskService;
import org.activiti.engine.task.IdentityLink;
import org.activiti.engine.task.IdentityLinkType;
import org.activiti.engine.task.TaskQuery;
import org.activiti.runtime.api.model.impl.APITaskConverter;
import org.activiti.runtime.api.model.impl.APIVariableInstanceConverter;
import org.activiti.runtime.api.query.impl.PageImpl;
import org.springframework.security.access.prepost.PreAuthorize;

@PreAuthorize("hasRole('ACTIVITI_ADMIN')")
public class TaskAdminRuntimeImpl implements TaskAdminRuntime {

    private final TaskService taskService;

    private final APITaskConverter taskConverter;

    private final APIVariableInstanceConverter variableInstanceConverter;

    private final TaskRuntimeHelper taskRuntimeHelper;

    private final SecurityManager securityManager;

    public TaskAdminRuntimeImpl(TaskService taskService,
                                APITaskConverter taskConverter,
                                APIVariableInstanceConverter variableInstanceConverter,
                                TaskRuntimeHelper taskRuntimeHelper,
                                SecurityManager securityManager) {
        this.taskService = taskService;
        this.taskConverter = taskConverter;
        this.variableInstanceConverter = variableInstanceConverter;
        this.taskRuntimeHelper = taskRuntimeHelper;
        this.securityManager = securityManager;
    }

    @Override
    public Task task(String taskId) {
        return taskConverter.from(taskRuntimeHelper.getInternalTask(taskId));
    }

    @Override
    public Page<Task> tasks(Pageable pageable) {
        return tasks(pageable,
                TaskPayloadBuilder.tasks().build());
    }

    @Override
    public Page<Task> tasks(Pageable pageable,
                            GetTasksPayload getTasksPayload) {
        TaskQuery taskQuery = taskService.createTaskQuery();

        if (getTasksPayload.getProcessInstanceId() != null) {
            taskQuery = taskQuery.processInstanceId(getTasksPayload.getProcessInstanceId());
        }
        if (getTasksPayload.getParentTaskId() != null) {
            taskQuery = taskQuery.taskParentTaskId(getTasksPayload.getParentTaskId());
        }

        List<Task> tasks = taskConverter.from(taskQuery.listPage(pageable.getStartIndex(),
                pageable.getMaxItems()));
        return new PageImpl<>(tasks,
                Math.toIntExact(taskQuery.count()));
    }

    @Override
    public Task update(UpdateTaskPayload updateTaskPayload) {
        return taskRuntimeHelper.applyUpdateTaskPayload(true, updateTaskPayload);
    }

    @Override
    public Task delete(DeleteTaskPayload deleteTaskPayload) {

        //      we might need to create an empty shell with the task ID and Status only
        Task task = task(deleteTaskPayload.getTaskId());

        TaskImpl deletedTaskData = new TaskImpl(task.getId(),
                task.getName(),
                Task.TaskStatus.CANCELLED);

        String authenticatedUserId = securityManager.getAuthenticatedUserId();

        if (!deleteTaskPayload.hasReason()) {
            deleteTaskPayload.setReason("Task deleted by " + authenticatedUserId);
        }

        taskService.deleteTask(deleteTaskPayload.getTaskId(),
                deleteTaskPayload.getReason(),
                true);
        return deletedTaskData;
    }

    @Override
    public List<VariableInstance> variables(GetTaskVariablesPayload getTaskVariablesPayload) {
        return variableInstanceConverter.from(taskRuntimeHelper.getInternalTaskVariables(getTaskVariablesPayload.getTaskId()).values());
    }

    @Override
    public void createVariable(CreateTaskVariablePayload createTaskVariablePayload) {
        taskRuntimeHelper.createVariable(true, createTaskVariablePayload);
    }

    @Override
    public void updateVariable(UpdateTaskVariablePayload updateTaskVariablePayload) {
        taskRuntimeHelper.updateVariable(true, updateTaskVariablePayload);
    }

    @Override
    public Task complete(CompleteTaskPayload completeTaskPayload) {
        Task task = task(completeTaskPayload.getTaskId());
        if (task == null) {
            throw new IllegalStateException("Task with id: " + completeTaskPayload.getTaskId() + " cannot be completed because it cannot be found.");
        }
        
        taskRuntimeHelper.handleCompleteTaskPayload(completeTaskPayload);
        
        TaskImpl competedTaskData = new TaskImpl(task.getId(),
                task.getName(),
                Task.TaskStatus.COMPLETED);
        taskService.complete(completeTaskPayload.getTaskId(),
                completeTaskPayload.getVariables(), true);
        return competedTaskData;
    }

    @Override
    public Task claim(ClaimTaskPayload claimTaskPayload) {
        taskService.claim(claimTaskPayload.getTaskId(),
                claimTaskPayload.getAssignee());

        return task(claimTaskPayload.getTaskId());
    }

    @Override
    public Task release(ReleaseTaskPayload releaseTaskPayload) {
        taskService.unclaim(releaseTaskPayload.getTaskId());
        return task(releaseTaskPayload.getTaskId());
    }

    @Override
    public Task assign(AssignTaskPayload assignTaskPayload) {
        //We need to release, claim for assigned task is not working!
        taskService.unclaim(assignTaskPayload.getTaskId());

        //Now assign a new user
        taskService.claim(assignTaskPayload.getTaskId(),
                assignTaskPayload.getAssignee());

        return task(assignTaskPayload.getTaskId());
    }

    @Override
    public void addCandidateUsers(CandidateUsersPayload candidateUsersPayload) {
        if (candidateUsersPayload.getCandidateUsers() != null && !candidateUsersPayload.getCandidateUsers().isEmpty()) {
            for ( String u : candidateUsersPayload.getCandidateUsers() ) {
                taskService.addCandidateUser(candidateUsersPayload.getTaskId(),
                        u);
            }
        }
    }

    @Override
    public void deleteCandidateUsers(CandidateUsersPayload candidateUsersPayload) {
        if (candidateUsersPayload.getCandidateUsers() != null && !candidateUsersPayload.getCandidateUsers().isEmpty()) {
            for ( String u : candidateUsersPayload.getCandidateUsers() ) {
                taskService.deleteCandidateUser(candidateUsersPayload.getTaskId(),
                        u);
            }
        }
    }

    @Override
    public void addCandidateGroups(CandidateGroupsPayload candidateGroupsPayload) {
        if (candidateGroupsPayload.getCandidateGroups() != null && !candidateGroupsPayload.getCandidateGroups().isEmpty()) {
            for ( String g : candidateGroupsPayload.getCandidateGroups() ) {
                taskService.addCandidateGroup(candidateGroupsPayload.getTaskId(),
                        g);
            }
        }
    }

    @Override
    public void deleteCandidateGroups(CandidateGroupsPayload candidateGroupsPayload) {
        if (candidateGroupsPayload.getCandidateGroups() != null && !candidateGroupsPayload.getCandidateGroups().isEmpty()) {
            for ( String g : candidateGroupsPayload.getCandidateGroups() ) {
                taskService.deleteCandidateGroup(candidateGroupsPayload.getTaskId(),
                        g);
            }
        }
    }

    @Override
    public List<String> userCandidates(String taskId) {
        List<IdentityLink> identityLinks = getIdentityLinks(taskId);
        List<String> userCandidates = new ArrayList<>();
        if (identityLinks != null) {
            for ( IdentityLink i : identityLinks ) {
                if (i.getUserId() != null) {
                    if (i.getType().equals(IdentityLinkType.CANDIDATE)) {
                        userCandidates.add(i.getUserId());
                    }
                }
            }

        }
        return userCandidates;
    }

    @Override
    public List<String> groupCandidates(String taskId) {
        List<IdentityLink> identityLinks = getIdentityLinks(taskId);
        List<String> groupCandidates = new ArrayList<>();
        if (identityLinks != null) {
            for ( IdentityLink i : identityLinks ) {
                if (i.getGroupId() != null) {
                    if (i.getType().equals(IdentityLinkType.CANDIDATE)) {
                        groupCandidates.add(i.getGroupId());
                    }
                }
            }

        }
        return groupCandidates;
    }

    private List<IdentityLink> getIdentityLinks(String taskId) {
        return taskService.getIdentityLinksForTask(taskId);
    }

}
